Arrannah

So I've gone and uninstalled and re-installed forge, java, Minecraft and I still cannot open the forge installer. My computer is up to date, my internet connection is better than ever and knowing me I know I've got to be missing something simple. I've never had so much trouble getting mods together on my Mac but in windows I cannot get past this step of installing forge. Every time I click it to open a window comes up so quick and re-closes before I can even see what it's about. Anyone have any step by steps on how to fix this? Also the mods folder was missing from my .minecraft files so I had to add it. I heard this was fairly common.